Eel River Ba'm (Green Sturgeon) Project
The Wiyot Tribe is continuing to develop its capacity to renew its traditional role as stewards of its natural resources. We were recently awarded grant funds through the National Marine Fisheries Service (NMFS)/National Oceanic and Atmospheric Association (NOAA) Species Recovery Grant to Tribes to complete a three-year study of Eel River ba'm, green sturgeon (Acipenser medirostris). The Wiyot Tribe, with technical assistance from Stillwater Sciences, is in the perfect position to successfully investigate green sturgeon in the Eel River and fill a critical data gap.
The goal of this project is to determine the current status and population of origin of North American green sturgeon in the Eel River. Green sturgeon in the Eel River comprise one of the most prominent data gaps for North American green sturgeon given that the Eel River is one of the larger rivers in California and had an apparently large and important historic spawning run. Ambiguity exists in terms of the current status of green sturgeon in the Eel River with official designations considering the spawning run lost and yet sightings still occurring annually.
According to NOAA’s recovery planning document for southern Distinct Population Segment (DPS) green sturgeon, “In order to establish a recovery plan for the species, the current status of that species must be understood.” This project will greatly improve that understanding by investigating one of the best potential unrecognized spawning runs. For whatever green sturgeon that still spawn in the Eel River, it is important to determine if they are northern DPS, as presumsed without evidence, or if they are southern DPS, or a mix. All possible outcomes would be significant: 1) if they are northern DPS then this would add a third spawning river to that population besides the Klamath and Rouge rivers; 2) if they are southern DPS then that would add a vital second spawning population besides the Sacramento River, with important implications for resiliency; and, 3) if they are a mix, then it would be the first documented mixed spawning run.
In addition to determining the population of origin, it’s important to document spawn timing and location, which can allow for a more accurate assessment of potential threats to successful reproduction and recovery in the Eel River. Another question to be answered is if the Eel River estuary, both the riverine and marine portions, are being used as rearing and feeding habitats for one or both DPSs of green sturgeon similar to nearby Humboldt Bay (mixed), or the Umpqua River estuary (northern DPS only), or the Klamath River (mixed in marine estuary, northern DPS only in riverine estuary).
The objectives of this project are to: 1) determine the presence, timing, and locations green sturgeon spawning and holding in the mainstem Eel River; 2) determine the population of origin (southern DPS vs. northern DPS) of these fish; and 3) determine the summer residence of green sturgeon in the Eel River estuary (riverine and marine). The project area will be from the confluence of the Middle Fork and mainstem at river mile 120 (Dos Rios) to the Pacific Ocean and the near shore marine portion of the estuary. It is important to conduct this study over a consecutive three year period to have an adequate baseline of data to meet the objectives given the spawning periodicity of green sturgeon.
Specific activities will include: 1) review of background scientific information and tribal oral histories and traditional ecological knowledge; 2) assess habitat availability and limitations by cataloguing pool depths and gathering available water temperature and flow data; 3) conduct a presence and enumeration survey on the mainstem Eel River using a mobile DIDSON sonar camera (192 river kilometers); 4) identify population(s) of origin using genetic analysis of any eggs collected with artificial substrate mats placed in likely spawning areas identified during the mobile DIDSON survey; 5) monitor for individuals tagged elsewhere by installing a sonic receiver detection network at strategic sites in the marine, estuarine, and riverine migration corridor; and, 6) report and disseminate findings in a manner that protects sensitive green sturgeon spawning and holding areas.
Eel River Spawning and Distribution Surveys in Wiyot Ancestral Water
The Natural Resources Department (NRD) has begun their second U.S. Fish and Wildlife Tribal Wildlife Grant (TWG) to conduct spawning and distribution surveys in Wiyot Ancestral waters. Surveys will be conducted on larger streams where Pacific lamprey are more common to utilize. The Department has begun ammocoete and spawning surveys and will partner with CA Department of Fish and Wildlife to install pit tags in Pacific lamprey at the weir located on Freshwater Creek.
Deliverable Reports from our recently completed second Pacific lamprey USFWS Tribal Wildlife Grant activities are below:
Eel River Pacific Lamprey Barrier Assessment and Limiting Factors Analysis
The NRD's first U.S. Fish and Wildlife TWG grant consisted of conducting lamprey barrier assessments on the Eel River and develop a Limiting Factors Analysis. A literature review was conducted by Abel Brumo (Stillwater Sciences) which helped clarify the urgent need for more extensive research focused on Pacific lamprey in the Eel River. The document is titled, Pacific Lamprey in the Eel River Basin: A Summary of Current Information and Identification of Research Needs. With the assistance of Stillwater Sciences, the Department has completed the final report titled, Evaluation of Barriers to Pacific Lamprey Migration in the Eel River Basin. The Department evaluated ~60 barriers within the Eel River watershed from Ferndale as far south as Willits. The project involved conducting habitat/ammocoete surveys, evaluating barrier characteristics and dimensions, and measuring longitudinal profiles and tailwater cross sections. The last phase of the project was the creation of a Eel River Pacific lamprey limiting factors analysis titled, A conceptual framework for understanding factors limiting Pacific lamprey production in the Eel River basin.
Baseline Monitoring of Estuaries on the North Coast of California
In cooperation with Humboldt State Univiersity, we are conducting monitoring of estuaries in Mendocino and Humboldt Counties. The objective of this project is to establish a baseline with which to monitor potential impacts of California's Marine Protected Areas. Furthermore, this is a great opportunity for capacity building and training in scientific monitoring techniques. We are monitoring Marine Protected Areas in Ten Mile, Big River, and Humboldt Bay, and a non-MPA in Mad River.
Cock Robin Island
In 2006, the Wiyot Tribe acquired approximately 100 acres on Cock Robin Island located in the Eel River estuary. The Department manages the island by monitoring water quality at an adjacent site and by performing bi-annual vegetation and avian surveys for species richness and abundance. The Tribe is currently working to convert the island from fee to trust status.